A user may use an IP multimedia subsystem (IP Multimedia Subsystem, IMS) for processing services. The services can be categorized into priority services and non-priority services. A priority service takes priority over a non-priority service.
At the time of carrying out a priority service in the prior art, a priority service bearer needs to be set up between the user equipment (User Equipment, UE) of a calling user and an IP connectivity access network (IP Connectivity Access Network, IP-CAN) accessed by the UE. The UE finishes the IMS registration by using the priority service bearer. A priority service session request of the calling user is routed by an emergency call session control function (Emergency Call Session Control Function, E-CSCF) in the IMS to an emergency call center, and the emergency call center provides the priority service.
However, the prior art supports only the priority service initiated proactively by a calling user, and does not support the priority service initiated from the network to a target user.